<SNIP> both had been opened, resealed, and put back on the shelf.</
Or, the customer bought one, carefully unpacked it (I use a razor
blade to make the minimal cuts in that plastic packaging), measured
his one or two rooms, re-packaged it and returned it saying "I just
couldn't get it to work as expected."
Some things you really need to try before committing - wish you could
do that with these @$(^)% computers and MS Operating Systems!